okayyy wait... is the main story their third life and this side story is their second life...

I don’t think so I’m pretty sure that this was before they met in their second life and just found someone who is similar I could be wrong

No its true. This side stroy is the first time they get reincarnated but only songyeon that remember. The second time they get reincarnated is the main story where both doesnt remember a thing. So basically its thirs time is a charm

Well at least they stay together forever ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄